U.S. rapid reaction teams have worked in South Sudan, where government troops are fighting rebels. / Jake Simkin, AP

by Jim Michaels, USA TODAY

by Jim Michaels, USA TODAY

WASHINGTON - The Marine Corps is developing plans to establish a contingency force that will be based in the Middle East and be capable of responding to crises throughout the troubled region.

The force is being planned as the United States reduces the size of its force in Afghanistan and has withdrawn combat forces from Iraq, shrinking its presence in a region plagued by violence and turmoil.

Planning for the force reflects an overall shift in strategy as the Pentagon winds up two large land wars and develops a smaller military designed for limited contingencies.

"The U.S. presence in the Persian Gulf is shifting from land to sea," said Loren Thompson, an analyst at the Lexington Institute. "That means greater reliance on the Marines for carrying out any missions on shore."

The force would be similar to a unit that the Marine Corps established in Moron, Spain, in the wake of the Sept. 11, 2012, attack on the U.S. Consulate in Benghazi, Libya, and would be capable of dispatching troops on a moment's notice to secure an embassy or evacuate Americans. An Army-led force operates out of the U.S. base at Camp Lemonnier in the East African nation of Djibouti.

The force is not designed to fight wars, but is organized and equipped to conduct small missions that require a quick response, such as evacuating an embassy under attack or securing U.S. property overseas.

The security environment is shifting toward "lots of little things that have to be done quickly," Thompson said.

The plans for the Marine force have not been finalized yet, said Capt. Eric Flanagan, a Corps spokesman.

Planners expect that the unit will maintain headquarters in Bahrain, a small Persian Gulf state that currently serves as headquarters to the U.S.Navy's 5th Fleet.

That will place the Marines closer to a region in near constant turmoil, including a civil war in Syria, a revolt in Egypt and a violent upsurge in Iraq.

The unit would operate under Central Command, the U.S. headquarters that oversees the war in Afghanistan and whose area of responsibility includes the Middle East.

Planners have not yet determined the size of the force, but the unit based in Moron has more than 500 servicemembers.

The Marines in that unit are coupled with aircraft and can take off on a mission within an hour of getting orders.

One of the lessons from the Benghazi attack, which killed U.S. Ambassador Christopher Stevens and three other Americans, was the need for dedicated forces in the region that could respond quickly to a call for help